/*
 * Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <stdlib.h>

/*
 * Uncomment this if the fallback non-builtin overflow checking is to
 * be tested.
 */
/*#define OPENSSL_NO_BUILTIN_OVERFLOW_CHECKING*/

#include "internal/nelem.h"
#include "internal/safe_math.h"
#include "testutil.h"

/* Create the safe math instances we're interested in */
OSSL_SAFE_MATH_SIGNED(int, int)
OSSL_SAFE_MATH_UNSIGNED(uint, unsigned int)
OSSL_SAFE_MATH_UNSIGNED(size_t, size_t)

static const struct {
    int a, b;
    int sum_err, sub_err, mul_err, div_err, mod_err, neg_a_err, neg_b_err;
    int abs_a_err, abs_b_err;
} test_ints[] = {
    { 1, 3,                 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { -1, 3,                0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 1, -3,                0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { -1, -3,               0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { INT_MAX, 1,           1, 0, 0, 0, 0, 0, 0, 0, 0 },
    { INT_MAX, 2,           1, 0, 1, 0, 0, 0, 0, 0, 0 },
    { INT_MIN, 1,           0, 1, 0, 0, 0, 1, 0, 1, 0 },
    { 1, INT_MIN,           0, 1, 0, 0, 0, 0, 1, 0, 1 },
    { INT_MIN, 2,           0, 1, 1, 0, 0, 1, 0, 1, 0 },
    { 2, INT_MIN,           0, 1, 1, 0, 0, 0, 1, 0, 1 },
    { INT_MIN, -1,          1, 0, 1, 1, 1, 1, 0, 1, 0 },
    { INT_MAX, INT_MIN,     0, 1, 1, 0, 0, 0, 1, 0, 1 },
    { INT_MIN, INT_MAX,     0, 1, 1, 0, 0, 1, 0, 1, 0 },
    { 3, 0,                 0, 0, 0, 1, 1, 0, 0, 0, 0 },
};

static int test_int_ops(int n)
{
    int err, r;
    const int a = test_ints[n].a, b = test_ints[n].b;

    err = 0;
    r = safe_add_int(a, b, &err);
    if (!TEST_int_eq(err, test_ints[n].sum_err)
            || (!err && !TEST_int_eq(r, a + b)))
        goto err;

    err = 0;
    r = safe_sub_int(a, b, &err);
    if (!TEST_int_eq(err, test_ints[n].sub_err)
            || (!err && !TEST_int_eq(r, a - b)))
        goto err;

    err = 0;
    r = safe_mul_int(a, b, &err);
    if (!TEST_int_eq(err, test_ints[n].mul_err)
            || (!err && !TEST_int_eq(r, a * b)))
        goto err;

    err = 0;
    r = safe_div_int(a, b, &err);
    if (!TEST_int_eq(err, test_ints[n].div_err)
            || (!err && !TEST_int_eq(r, a / b)))
        goto err;

    err = 0;
    r = safe_mod_int(a, b, &err);
    if (!TEST_int_eq(err, test_ints[n].mod_err)
            || (!err && !TEST_int_eq(r, a % b)))
        goto err;

    err = 0;
    r = safe_neg_int(a, &err);
    if (!TEST_int_eq(err, test_ints[n].neg_a_err)
            || (!err && !TEST_int_eq(r, -a)))
        goto err;

    err = 0;
    r = safe_neg_int(b, &err);
    if (!TEST_int_eq(err, test_ints[n].neg_b_err)
            || (!err && !TEST_int_eq(r, -b)))
        goto err;

    err = 0;
    r = safe_abs_int(a, &err);
    if (!TEST_int_eq(err, test_ints[n].abs_a_err)
            || (!err && !TEST_int_eq(r, a < 0 ? -a : a)))
        goto err;

    err = 0;
    r = safe_abs_int(b, &err);
    if (!TEST_int_eq(err, test_ints[n].abs_b_err)
            || (!err && !TEST_int_eq(r, b < 0 ? -b : b)))
        goto err;
    return 1;
 err:
    TEST_info("a = %d  b = %d  r = %d  err = %d", a, b, r, err);
    return 0;
}

static const struct {
    unsigned int a, b;
    int sum_err, sub_err, mul_err, div_err, mod_err;
} test_uints[] = {
    { 3, 1,                 0, 0, 0, 0, 0 },
    { 1, 3,                 0, 1, 0, 0, 0 },
    { UINT_MAX, 1,          1, 0, 0, 0, 0 },
    { UINT_MAX, 2,          1, 0, 1, 0, 0 },
    { 1, UINT_MAX,          1, 1, 0, 0, 0 },
    { 2, UINT_MAX,          1, 1, 1, 0, 0 },
    { UINT_MAX, 0,          0, 0, 0, 1, 1 },
};

static int test_uint_ops(int n)
{
    int err;
    unsigned int r;
    const unsigned int a = test_uints[n].a, b = test_uints[n].b;

    err = 0;
    r = safe_add_uint(a, b, &err);
    if (!TEST_int_eq(err, test_uints[n].sum_err)
            || (!err && !TEST_uint_eq(r, a + b)))
        goto err;

    err = 0;
    r = safe_sub_uint(a, b, &err);
    if (!TEST_int_eq(err, test_uints[n].sub_err)
            || (!err && !TEST_uint_eq(r, a - b)))
        goto err;

    err = 0;
    r = safe_mul_uint(a, b, &err);
    if (!TEST_int_eq(err, test_uints[n].mul_err)
            || (!err && !TEST_uint_eq(r, a * b)))
        goto err;

    err = 0;
    r = safe_div_uint(a, b, &err);
    if (!TEST_int_eq(err, test_uints[n].div_err)
            || (!err && !TEST_uint_eq(r, a / b)))
        goto err;

    err = 0;
    r = safe_mod_uint(a, b, &err);
    if (!TEST_int_eq(err, test_uints[n].mod_err)
            || (!err && !TEST_uint_eq(r, a % b)))
        goto err;

    err = 0;
    r = safe_neg_uint(a, &err);
    if (!TEST_int_eq(err, a != 0) || (!err && !TEST_uint_eq(r, 0)))
        goto err;

    err = 0;
    r = safe_neg_uint(b, &err);
    if (!TEST_int_eq(err, b != 0) || (!err && !TEST_uint_eq(r, 0)))
        goto err;
 
    err = 0;
    r = safe_abs_uint(a, &err);
    if (!TEST_int_eq(err, 0) || !TEST_uint_eq(r, a))
        goto err;

    err = 0;
    r = safe_abs_uint(b, &err);
    if (!TEST_int_eq(err, 0) || !TEST_uint_eq(r, b))
        goto err;
   return 1;
 err:
    TEST_info("a = %u  b = %u  r = %u  err = %d", a, b, r, err);
    return 0;
}

static const struct {
    size_t a, b;
    int sum_err, sub_err, mul_err, div_err, mod_err;
} test_size_ts[] = {
    { 3, 1,                 0, 0, 0, 0, 0 },
    { 1, 3,                 0, 1, 0, 0, 0 },
    { SIZE_MAX, 1,          1, 0, 0, 0, 0 },
    { SIZE_MAX, 2,          1, 0, 1, 0, 0 },
    { 1, SIZE_MAX,          1, 1, 0, 0, 0 },
    { 2, SIZE_MAX,          1, 1, 1, 0, 0 },
    { 11, 0,                0, 0, 0, 1, 1 },
};

static int test_size_t_ops(int n)
{
    int err;
    size_t r;
    const size_t a = test_size_ts[n].a, b = test_size_ts[n].b;

    err = 0;
    r = safe_add_size_t(a, b, &err);
    if (!TEST_int_eq(err, test_size_ts[n].sum_err)
            || (!err && !TEST_size_t_eq(r, a + b)))
        goto err;

    err = 0;
    r = safe_sub_size_t(a, b, &err);
    if (!TEST_int_eq(err, test_size_ts[n].sub_err)
            || (!err && !TEST_size_t_eq(r, a - b)))
        goto err;

    err = 0;
    r = safe_mul_size_t(a, b, &err);
    if (!TEST_int_eq(err, test_size_ts[n].mul_err)
            || (!err && !TEST_size_t_eq(r, a * b)))
        goto err;

    err = 0;
    r = safe_div_size_t(a, b, &err);
    if (!TEST_int_eq(err, test_uints[n].div_err)
            || (!err && !TEST_size_t_eq(r, a / b)))
        goto err;

    err = 0;
    r = safe_mod_size_t(a, b, &err);
    if (!TEST_int_eq(err, test_size_ts[n].mod_err)
            || (!err && !TEST_size_t_eq(r, a % b)))
        goto err;

    err = 0;
    r = safe_neg_size_t(a, &err);
    if (!TEST_int_eq(err, a != 0) || (!err && !TEST_size_t_eq(r, 0)))
        goto err;

    err = 0;
    r = safe_neg_size_t(b, &err);
    if (!TEST_int_eq(err, b != 0) || (!err && !TEST_size_t_eq(r, 0)))
        goto err;
 
    err = 0;
    r = safe_abs_size_t(a, &err);
    if (!TEST_int_eq(err, 0) || !TEST_size_t_eq(r, a))
        goto err;

    err = 0;
    r = safe_abs_size_t(b, &err);
    if (!TEST_int_eq(err, 0) || !TEST_size_t_eq(r, b))
        goto err;
    return 1;
 err:
    TEST_info("a = %zu  b = %zu  r = %zu  err = %d", a, b, r, err);
    return 0;
}

static const struct {
    int a, b, c;
    int err;
} test_muldiv_ints[] = {
    { 3, 1, 2,                          0 },
    { 1, 3, 2,                          0 },
    { -3, 1, 2,                         0 },
    { 1, 3, -2,                         0 },
    { INT_MAX, INT_MAX, INT_MAX,        0 },
    { INT_MIN, INT_MIN, INT_MAX,        1 },
    { INT_MIN, INT_MIN, INT_MIN,        0 },
    { INT_MAX, 2, 4,                    0 },
    { 8, INT_MAX, 4,                    1 },
    { INT_MAX, 8, 4,                    1 },
    { INT_MIN, 2, 4,                    1 },
    { 8, INT_MIN, 4,                    1 },
    { INT_MIN, 8, 4,                    1 },
    { 3, 4, 0,                          1 },
};

static int test_int_muldiv(int n)
{
    int err = 0;
    int r, real = 0;
    const int a = test_muldiv_ints[n].a;
    const int b = test_muldiv_ints[n].b;
    const int c = test_muldiv_ints[n].c;

    r = safe_muldiv_int(a, b, c, &err);
    if (c != 0)
        real = (int)((int64_t)a * (int64_t)b / (int64_t)c);
    if (!TEST_int_eq(err, test_muldiv_ints[n].err)
            || (!err && !TEST_int_eq(r, real))) {
        TEST_info("%d * %d / %d  r = %d  err = %d", a, b, c, r, err);
        return 0;
    }
    return 1;
}

static const struct {
    unsigned int a, b, c;
    int err;
} test_muldiv_uints[] = {
    { 3, 1, 2,                          0 },
    { 1, 3, 2,                          0 },
    { UINT_MAX, UINT_MAX, UINT_MAX,     0 },
    { UINT_MAX, 2, 4,                   0 },
    { 8, UINT_MAX, 4,                   1 },
    { UINT_MAX, 8, 4,                   1 },
    { 3, 4, 0,                          1 },
};

static int test_uint_muldiv(int n)
{
    int err = 0;
    unsigned int r, real = 0;
    const unsigned int a = test_muldiv_uints[n].a;
    const unsigned int b = test_muldiv_uints[n].b;
    const unsigned int c = test_muldiv_uints[n].c;

    r = safe_muldiv_uint(a, b, c, &err);
    if (c != 0)
        real = (unsigned int)((uint64_t)a * (uint64_t)b / (uint64_t)c);
    if (!TEST_int_eq(err, test_muldiv_uints[n].err)
            || (!err && !TEST_uint_eq(r, real))) {
        TEST_info("%u * %u / %u  r = %u  err = %d", a, b, c, r, err);
        return 0;
    }
    return 1;
}

int setup_tests(void)
{
    ADD_ALL_TESTS(test_int_ops, OSSL_NELEM(test_ints));
    ADD_ALL_TESTS(test_uint_ops, OSSL_NELEM(test_uints));
    ADD_ALL_TESTS(test_size_t_ops, OSSL_NELEM(test_size_ts));
    ADD_ALL_TESTS(test_int_muldiv, OSSL_NELEM(test_muldiv_ints));
    ADD_ALL_TESTS(test_uint_muldiv, OSSL_NELEM(test_muldiv_uints));
    return 1;
}